The Invo is designed to be more of a ultra high performance dry/wet tire, treadwear rating is 260, the Motivo adds an all season tread design and wear rating of 560, not quite as sticky, longer expected life.
That's just Discount Tire, they don't allow their stores to sell or install spacers so you will get the "they're bad for you" speech. My company sells over 50,000 bolt on spacers/adapters every year and a failure is extremely rare, when it has happened it always stems from being installed...